Process for converting an asphalt containing petroleum residual oil by catalytic hydrocracking



United States Patent PRGCESS FOR CONVERTING AN ASPHALT CQN- TAINENG PETRQLEUM REIDUAL GEL BY CAT- ALYTIC HYDROCRAfiKING Carl D. Keith, Summit, N.J., and Henry Erickson, Park Forest, Ill, assignors, by mesne assignments, to Sinciair Research, lino, New York, N.Y., a corporation of Deiaware N0 Drawing. Fiied Apr. 7, 1960, er. No. 20,532

5 Claims. (1. 208-48) The present invention relates to the conversion of asphalt-containing petroleum residual fractions to provide improved reforming feedstocks, heating oils and cracking stocks.

In the prior art processes for the conversion of asphaltcontaining residual fractions, the fractions are generally first hydrogenated in the presence of a suitable catalyst under conditions of temperature and pressure which result in cracking as well as hydrogenation. When this is done, however, the catalysts commonly employed promote hydrogenation of both the lower boiling components in the feed, for, instance, those in the 950 F. boiling range and the higher boiling components, for instance, the 950 F.+ fraction with the result that relatively high hydrogen consumption occurs. Consequently large amounts of hydrogen are los-tby way of hydrogenation to what is generally considered the less desirable fraction, that is the high boiling component for instance, the 950 F.+ fractions. Subsequent hydro-treating operations to which the lower boiling components are often subjected will require yet more hydrogen. Moreover, the catalysts commonly employed rapidly deactivate particularly as far as conversion is concerned; the conversion rate quickly decreasing after a short period of time.

In accordance with the present invention we have discovered a new and improved process for the conversion of asphalt-containing petroleum residual fractions to provide upgraded reforming feedstock, heating oils, and cracking stock which process includes a hydrocracking oper ation wherein the hydrogen consumed is primarily by the more desirable fraction i.e. the lower boiling components, for instance, the 950 F. minus fraction; the total hydrogen consumption consequently being relatively small. Moreover the conversion level of catalyst activity does not quickly decrease after a short period of time. The process of the present invention involves passing the asphalt-containing residual together with hydrogen into contact with a particular catalyst under hydrocracking conditions, separating the product into a lighter fraction and a heavier fraction, hydrotreating the lighter fraction in the presence of a hydrogenation catalyst and recovering one or more fractions which can serve as reforming stock, heating oil or cracking stock.

The asphalt and sulfur-containing petroleum residual feed of the present invention is generally heavy residual crude material that contains asphaltenes and maltenes, as for example, penetration range asphalts having a penetration of about 250 or less at 77 F. The particular catalyst employed in the hydrocracking step is comprised of cobalt and molybdena on acid-treated halloysite clay, for example, mineral acid, such as sulfuric acid, treated hal loysite clay. It has been found that use of this catalyst in the hydrocracking operation of the present invention, unlike other commonly employed hydrogenation catalysts, unexpectedly pro-motes hydrogenation of the lower boiling or lighter fractions with little hydrogenation of the heavier fractions. Thus good yields of the lighter fractions are gained with relatively small hydrogen consump tion. At the same time the catalyst exhibits good activity 3,079,327 Patented Feb. 26, 1953 with little tendency to deactivate as far as conversion is concerned.

The catalyst of the present invention can be prepared by providing an acid-treated halloysite clay with catalytic amounts of cobalt and molybdena and calcining the composite. Calcination temperatures employed are those known in the art, for example, about 600 to 1300 F. or more. Ordinarily the cobalt and molybdena will be present in catalytic amounts of about 1.0 to 10.0 percent cobalt and about 6.0 to 20.0 percent molybdena. The com bination of cobalt and molybdenum on a catalyst calcined after these components are added to the catalyst base as in the present invention is sometimes referred to as cobalt molybdate. The acid-treated clay may contain in addition to that naturally present minor amounts, preferably less than about 25 weight percent, of alumina.

The hydrocracking step of our process generally employs elevated pressure conditions, for instance within the range of about 500 to 5000 p.s.i.g., preferably about 2200 to 2700 p.s.i.g. The temperature used in the hydrocracking step is usually about 600 to 900 F., preferably about 780m 800 F. The free hydrogen employed is generally about 1000 to 6000 or more cubic feet per barrel of fresh residual feed and it is convenient to provide most of the hydrogen by recycle of gas. Make-up hydrogen can be added as needed at a hydrogen consumption rate of about to 600 cubic feet per barrel of feed. The weight hourly space velocity (WHSV) weight units of feed introduced into the reaction zone per weight unit catalyst per hour, will usually be within the range of about 0.3 to 2.

The product from the hydrocracking operation can be separated into the heavier and lighter material fractions by any convenient means known to the art, preferably under high pressure. Although the separation point can be varied, ordinarily a separation is made within the vicinity of about 800 to 1000 P. so that the heavier fraction will generally constitute a material having an initial boiling point within the range of about 800 to 1000 F. and the lighter material an end boiling point in the range of about 800 to 1000 F. A preferred separation point is about 950 F.

In the second stage of our process the lighter fraction is hydrotreated under hydrogenation conditions and in the presence of a hydrogenation catalyst to remove sulfur and saturate the olefins contained in the light fraction. Examples of suitable catalyst ingredients are any of the hydrogenation catalysts such as molybdenum, tungsten, vanadium, tin, chromium, the group VIII metals, for instance, iron, cobalt, nickel, platinum group metals, and their oxides and sulfides. Mixtures of these materials or compounds or two or more of the oxides can be employed. Minor catalytic amounts, e.g. usually less than about 10 or 20%, of these ingredients can be dispersed on or carried as promoters by other materials such as oxides, silicates or mixtures of the oxides and silicates. The composite is then calcined after the promoting metal is added. Synthetic catalysts of this type are generally the activated oxides of aluminum and the like, mixtures of oxides of silica with oxides of magnesium, boron, aluminum, titanium, and zirconium. Specific examples of suitable hydrogenation catalysts are cobalt-molybdena-on-alumina, nickel-tungsten oxide-on-alumina, nickel-tungsten sulfideon-alumina, and cobalt-molybdena-on-silica-alumina. The hydrogenation conditions employed generally will fall within the following ranges: temperature, about 550 to 800 F.; pressure, about 200 to 800 p.s.i.g.; weight hourly space velocity 1 to 8; hydrogen recycle, about 500 to 5000 standard cubic feet per barrel of feed. The hydrotreated light fraction from the second stage of our process can be sent to a fractionator to obtain a reforming fraction, e.g. a fraction boiling in the gasoline range and heavy fractions such as heating oil and catalytic crack- EXAMPLE II ing stock. Io demonstrate the advantages of using cobalt molyb- The following examples illustrate the invention. denum acid-treated halloysite clay catalyst in the hydro- .EXAMPLE I cracking stage of the present invention, comparative runs 5 were made under conditions similar to Example I but I:o ayelma asphalt produced as bottoms 1n thevacuum employing i {he h dro kj Stage the f ll i d stlllfl n 'cru fl Petroleum 011 based Crude) alysts: cobalt-molybdena-on-alumina and cobalt-molybhydrogen g wasfidded-afld rate W -S dena-on-silica-alumina. The results of tests on the '950" cubic feet P barrel of asphalt feed- The mixture Wa F. minus and950 F plus liquid products are alsoshown then introduced into a hydrocracking reactor. Reactor 10 in Table I.

7 Table No. 1

Run No. R46 C01\I00t+A1z03 ooMo04+s1orAn0= 017M001 Acid-Treated Trihydrate A1202 Halloysite Clay -3 48-54 64-30 0-8 32-43 64-30. 0-3 32-43 64-80 1 1.3 1.2 1.7 1.5 1.7 2.3 1.8 1.7 1.6 7.3 4.3 3.4 6.3 5.9 4.6 5.3 5.5 5.0 17. 0 11. 6 14. 2 17. 6 15.8 15. 2 13. s .13. 7 14.0 29. 0 10. 6 19. 2 22.1 25.3: 25. 7 14. 4 .13. 5 .19. 0 35. 3 62. 2 57. 0 41. 0 47. 0 43. 0 55. 7 57. 3 56.1 3.9 0.2 0.1 4.0 0.2 0.2 3.7 0.2 0.2 Hz Consump. s.c.f.lbol 856 .505 495: 300 650 420 540. 245 320 Conversion to 950 1*. minus. 60. 8 :37. 6 12. 9 .55. 0 52. 8 .51. 8 39. 6. 42. 5. -43. s sm )3. 'API 52.0 52.4 55. 2 5410' 54. s 53.0 52.3 50.6 53;

7. 3 19. 0 20.1 6. 5 17. 0 21. 9 2e. 7 36. s, 40. 14. 3; 9.8 6;9' 13. s; 10. 7 '11. 1; 12. 3 13: 5 10;

' l V I 49. 2 51. 5 46. 3 45. 4' .46. 2 42. 4 43. 0 41. 7.3 19.0 20. 1 5. 5 21. 9- 25.7 as. a 40. 30.2 13. 9 24. 2 34. 0 21. 7, 13; 7 10.3 9. 12.3. 10.5 3.9 14.1 p 10.2 12.2 9.9 3. 35. 1 33.6- 32.2 32 a 34. 9 34. 3 32. 3 32. 4 33. Bromine'No 22.9 23.0 22.5 11.71 19:5 22.7 29.3 33.7 .33. Percent Sulfur 0.461 0.59 0.13 0.14 0. 36. 0.51 1.11 1.22 1.2 Carbon Residue'DlSQ 0. 03 Nes 0. 01 0.06 0. 02 0.02 0. 05 0. 01 0; 0 GEO-950 F. Parr. Nes, 20.2: 2017 20. 4 r19. 81 19. 3 19. 0; 1s. 9. .-13.3 Percent Sulfur 0. 79 0. 33 0. 75 0. 91 1. 31 1. 52 1. 9 Carbon Residue 0. 52 037 0. 38 0= 89 0. 70 0. 56 1.33 1.37 1950" 13. Btms. API 3-5 3.0 7. 4 9.3 7 3 =3. 7 6. 7. 2-4 0.7 Percent Sulfur 1.18 1. 52 1. 39 0. 93 1-52 1. 46. 1. 32 2.26 2.40 "CarbonResidue 23.5 23.- 4 22- 6 2L 5 24- 1 23. 6 '23. 7 '33. 4 36:0 Metals by ES:

N10, p.p.m 94 133 122 55 100' 120 115' 218 '250 V505. p.p.m.-- 205 253 241 120 .2001 330: .255: .350 740 was provided with a catalyst bed of a calcined cobaltmolybdena-on-acid treated halloysite clay. The catalyst analyzed approximately 2.5% Co-and 8.5% M00 The amount of catalyst present in the reactor was such that the weight hourly space velocity was .8 based on the total fresh feed. The temperature:in the hydrocra-cking reactor was about 820 F. and the pressure about 1000 p.s.i .-g. The product together with the unconsumed hydrogen was removed from the bottom of the reactor and introducedv into a flash drum. Unconsumed hydrogen as well ascertain volatile constituents of the product were recoveredoverhead'and passed to an absorber to purify the hydrogen. The hydrogen from the absorber wasrecycledat -a rate of 4000 s.c.f./ b. to the hydrogen line and hence into the reactor. The liquid product was removedfrom the flash-drum and introduced into a superatrnospheric fractionating'colurnn. In the fractionation column the liquid product'was split into a 950 F. minus tractionrand a 950.F. plus fraction (based on atmospheric pressure). Composites of tests of a series-of runs were made to obtainproduct inspection from 0-8, 32-48, 48-64 and 64-80 hours on stream. Table 1 lists the results of these tests.

The 950 F. minus fraction from each run is then sent to a hydrogenation zone. The hydrogenation zone is provided with a bed of cobalt-molybdena-on-alumina catalyst and hydrogen gas at a rate of 3500 s.c.f./ b. The catalyst analyzes 2.5% cobalt and 6% molybdenum. The zone is operated eta temperature of 680 F. and a pressure of -500'p.s.i.g. The amountof catalyst present was such that the weight hourly-space velocity based on'the totalfced-waslO. .The'hydrotreated (hydrogenated and desuliurized) product then is sent to a fractionator. In the. fractionator a reformingstock. having an end boiling pointof about 400 Rand a cracking stock and heating oil .having aninitial boilingpoint of about 400 F. and an end boiling point of about'950 are obtained.

Examination of the data of T able I shows the ability of the catalyst .of the .presentinventionto promote the selective hydrocrackin-g reaction with relatively small consumption of hydrogen whereas other hydrocracking catalysts although aifording hydrocracking of. asphaltic feedstocks cannot upgrade the asphaltic feed without substantial consumption'of hydrogen, yet the API gravities in the 950 F. minus fractions obtained by our hydrocracking operation are good. The data also show that the catalyst did not deactivate as far as conversion is concerned over an 80'hour period and that the catalyst was relatively clean. The low hydrogen consumption and perhaps other factors result in a.950 'F.+ fraction which is relatively unrefined, i.e. as compared with that from the use of non-halloysite based catalysts, and the heavy fraction is high in sulfur, carbon residue and cat .alyst-poisoning metals and of low gravity. Thus the first step of the process is selective towards improving the more valuable light products which are to be hydrogenated in our second stage and hydrogen is not lost to the relatively less desirable 950 F.+ fraction.

We claim:

1. A process for the conversion of asphalt containing petroleum residuals which comprises passing an asphaltcontaining petroleum residual fraction and hydrogen under hydrocracking conditions, including a temperature from about 600 to 900 F. and elevated pressure, into contact with a calcined catalyst consistingessentially of catalytic amounts of cobalt and molybdena on acidtreated halloysite clay, separating the resulting product at a separation point within the range .of about 800 to 1000 F. into a heavierfraction and a lighterfraction, hydrotreating the lighter fraction under hydrogenation conditions and in the presence of a hydrogenation catalyst.

2. The process of claim 1 wherein the hydrocracking conditions include a temperature of about 780 to 800 F. and a. pressure of about 2200 tov 27 00 p.s.i.g.

3. The process of claim 1 wherein the lighter fraction has an end boiling point of about 950 F.

4. The process of claim 1 wherein the hydrotreating step is conducted in the presence of a hydrogenation catalyst at a temperature of about 550 to 800 'F., a pressure of about 200 to 800 p.s.i.g.

5. The process of claim 4 wherein the hydrogenation catalyst is cobalt molybdena on alumina.

References Cited in the file of this patent UNITED STATES PATENTS Ofiuit et a1. May 1, 1956 Keith Sept. 23, 1956 Dinwidclie et a1. Sept. 1, 1959 Reif et a1. Oct. 13, 1959 Mills et a1. Nov. 24, 1959 

1. A PROCESS FOR THE CONVERSION OF ASPHALT-CONTAINING PETROLEUM RESIDUALS COMPRISES PASSING AN ASPHALTCONTAINING PETROLEUM RESIDUAL FRACTION AND HYDROGEN UNDER HYDROCRACKING CONDITIONS, INCLUDING A TEMPREATURE FROM ABOUT 600 TO 900*F. AND ELEVATED PRESSURE, INTO CONTACT WITH A CALCINED CATALYST CONSISTING ESSENTIALLY OF CATALYTIC AMOUNTS OF COBALT AND MOLYBDENA ON ACIDTREATED HALLOYSITE CLAY, SEPARATING THE RESULTING PRODUCT AT A SEPARATION POINT WITHIN THE RANGE OF ABOUT 800 TO 1000*F. INTO A HEAVIER FRACTION AND A LIGHTER FRACTION, HYDROTREATING THE LIGHTER FRACTION UNDER HYDROGENATION CONDITIONS AND IN THE PRESENCE OF A HYDROGENATION CATALYST. 